Researchers are urging Maryland voters to check the accuracy of their online voter registration files after warning that the data had been left vulnerable to tampering.

According to a Washington Post report, researchers at the University of Michigan, the Lawrence Livermore National Laboratory and a former president of the Association for Computing Machinery contacted Maryland officials and noted that anyone with access to a Maryland voter’s full name and birth date could exploit an online tool to change the voter’s address, party affiliation or other information. Such changes, especially a change of address, could lead to a voter’s ballot not being counted normally on Election Day, the report says.

According to the report, the crux of the problem is that Maryland linked its voter registration files to the state’s database of driver’s license numbers.

"That move was designed to add a layer of security and to weed out suspicious voter files. But in Maryland, driver’s license numbers are derived from a resident’s name and birth date. Several Web sites can decode a driver’s license number using the latter two pieces of information. The researchers discovered Maryland’s problem after finding a similar vulnerability in Washington state’s new online voter registration system," the report says.

Researchers said that with a relatively simple code, a computer attack could change the voter registration files of thousands of Maryland residents, and probably do so in a way that could avoid detection.

The researchers said the state had exacerbated the potential for tampering by not instituting basic safeguards, the report says.